Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 92	$ 62
Accounts receivable, less allowance for expected credit losses	409	475
Production fuel, at weighted average cost	65	62
Gas stored underground, at weighted average cost	52	79
Materials and supplies, at weighted average cost	206	202
Regulatory assets	212	232
Other	178	160
Total current assets	1,214	1,272
Property, plant and equipment, net	17,706	17,157
Investments:
ATC Holdings	400	386
Other	223	216
Total investments	623	602
Other assets:
Regulatory assets	2,133	2,029
Deferred charges and other	160	177
Total other assets	2,293	2,206
Total assets	21,836	21,237
Current liabilities:
Current maturities of long-term debt	804	809
Commercial paper	52	475
Accounts payable	581	611
Regulatory liabilities	110	107
Other	307	302
Total current liabilities	1,854	2,304
Long-term debt, net (excluding current portion)	8,900	8,225
Other liabilities:
Deferred tax liabilities	2,086	2,042
Regulatory liabilities	1,026	1,023
Pension and other benefit obligations	240	249
Other	939	617
Total other liabilities	4,291	3,931
Commitments and contingencies (Note 14)
Common equity:
Common stock	3	3
Additional paid-in capital	3,042	3,030
Retained earnings	3,755	3,756
Accumulated other comprehensive income	3	1
Shares in deferred compensation trust - 352,514 and 379,006 shares at a weighted average cost of $35.38 and $34.48 per share	(12)	(13)
Total common equity	6,791	6,777
Total liabilities and equity	21,836	21,237
IPL [Member]
Current assets:
Cash and cash equivalents	9	53
Accounts receivable, less allowance for expected credit losses	186	242
Production fuel, at weighted average cost	36	27
Gas stored underground, at weighted average cost	18	35
Materials and supplies, at weighted average cost	123	122
Regulatory assets	84	93
Other	68	51
Total current assets	524	623
Property, plant and equipment, net	8,670	8,298
Other assets:
Regulatory assets	1,464	1,484
Deferred charges and other	74	84
Total other assets	1,538	1,568
Total assets	10,732	10,489
Current liabilities:
Current maturities of long-term debt	500	500
Accounts payable	252	262
Accrued taxes	56	50
Accrued interest	39	40
Regulatory liabilities	62	72
Other	110	101
Total current liabilities	1,019	1,025
Long-term debt, net (excluding current portion)	3,446	3,445
Other liabilities:
Deferred tax liabilities	1,150	1,091
Regulatory liabilities	556	572
Pension and other benefit obligations	48	51
Other	433	331
Total other liabilities	2,187	2,045
Commitments and contingencies (Note 14)
Common equity:
Common stock	33	33
Additional paid-in capital	3,012	2,887
Retained earnings	1,035	1,054
Total common equity	4,080	3,974
Total liabilities and equity	10,732	10,489
WPL [Member]
Current assets:
Cash and cash equivalents	80	7
Accounts receivable, less allowance for expected credit losses	209	219
Production fuel, at weighted average cost	30	35
Gas stored underground, at weighted average cost	34	44
Materials and supplies, at weighted average cost	79	77
Regulatory assets	128	139
Prepaid gross receipts tax	49	49
Other	38	43
Total current assets	647	613
Property, plant and equipment, net	8,554	8,415
Other assets:
Regulatory assets	669	545
Deferred charges and other	55	61
Total other assets	724	606
Total assets	9,925	9,634
Current liabilities:
Commercial paper	0	318
Accounts payable	261	293
Accrued interest	46	40
Regulatory liabilities	48	35
Other	83	89
Total current liabilities	438	775
Long-term debt, net (excluding current portion)	3,368	3,070
Other liabilities:
Deferred tax liabilities	804	827
Regulatory liabilities	470	451
Pension and other benefit obligations	114	121
Other	721	493
Total other liabilities	2,109	1,892
Commitments and contingencies (Note 14)
Common equity:
Common stock	66	66
Additional paid-in capital	2,533	2,478
Retained earnings	1,411	1,353
Total common equity	4,010	3,897
Total liabilities and equity	$ 9,925	$ 9,634